var KEY = {
	W: 87,
	A: 65,
	S: 83,
	D: 68,
}
function press(event) {
	var code = event.keyCode;
	switch (code) {
		case KEY.W:
			tankPlayer1.direction = 'up';
			move(tankPlayer1, 'up');
			break;
		case KEY.A:
			tankPlayer1.direction = 'left';
			move(tankPlayer1, 'left');
			break;
		case KEY.S:
			tankPlayer1.direction = 'down';
			move(tankPlayer1, 'down');
			break;
		case KEY.D:
			tankPlayer1.direction = 'right';
			move(tankPlayer1, 'right');
			break;
	}
}